Representation in development: from a model system to some general processes

Back to basics: A re-evaluation of the relevance of imprinting in the genesis of Bowlby's attachment theory

Attachment theory is one of the key theoretical constructs that underpin explorations of human bonding, taking its current form in John Bowlby's amalgamation of ideas from psychoanalysis, developmental psychology and ethology. Such a period of interdisciplinary exchange, and Bowlby's interest in Lorenz' concept of imprinting in particular, have been subject to rather historical and biographical studies, leaving a fine-grained theoretical scrutiny of the exact relationship between imprinting and attachment still pending. This paper attempts to remedy such an omission by exploring the relationships between these two constructs. It critically reviews the theories of imprinting in general, of human imprinting in particular, and of attachment; analysis of the links between these processes bring to the foreground the distinction between supra-individual vs. individual aspects of bonding, the relevance of 'proto-attachment' phases before 'proper' Bowlbyan attachment is attained, and the role of communicative signals during such early phases. The paper outlines potential benefits of considering such elements in the study of early social cognition, particularly in respect of the study of the gaze and the infant-directed communicative register.

Perceptual learning with tactile stimuli in rodents: Shaping the somatosensory system

The animal kingdom contains species with a wide variety of sensory systems that have been selected to function in different environmental niches, but that are also subject to modification by experience during an organism’s lifetime. The modification of such systems by experience is often called perceptual learning. In rodents, the classic example of perceptual learning is the observation that simple preexposure to two visual stimuli facilitates a subsequent (reinforced) discrimination between them. However, until recently very little behavioral research had investigated perceptual learning with tactile stimuli in rodents, in marked contrast to the wealth of information about plasticity in the rodent somatosensory system. Here we present a selective review of behavioral analyses of perceptual learning with tactile stimuli, alongside evidence concerning the potential bases of such effects within the somatosensory system.

The role of stimulus comparison in animal perceptual learning: Effects of a distractor placement

Research on perceptual learning shows that the way stimuli are presented leads to different outcomes. The intermixed/blocked (I/B) effect is one of these outcomes, and different mechanisms have been proposed to explain it. In human research, it seems that comparison between stimuli is important, and the placement of a distractor between the pre-exposed stimuli interferes with the effect. Results from animal research are usually interpreted in different terms because the type of procedure normally used in animal perceptual learning does not favour comparison. In our experiments, we explore the possibility that a distractor placed between the to-be-discriminated stimuli may interfere with the perceptual learning process in rats. In Experiment 1, two flavoured solutions are presented in an I/B fashion, with a short time lapse between them to favour comparison, showing the typical I/B effect. In Experiment 2, we introduced a distractor in between the solutions, abolishing this effect. Experiment 3 further replicates this by comparing two intermixed groups with or without distractor. The results replicate the findings from human research, suggesting that comparison also plays an important role in animal perceptual learning.

Perceptual learning with tactile stimuli in rats: Changes in the processing of a dimension

Four experiments with male rats investigated perceptual learning involving a tactile dimension (A, B, C, D, E), where A denotes 1 end of the continuum (e.g., a rough floor) and E the other (e.g., a smooth floor). In Experiment 1, rats given preexposure to A and E learned an appetitive discrimination between them more readily than those not given preexposure. Experiment 2a showed that rats preexposed to B and D acquired a discrimination between A and E more readily than those preexposed to A and E; and in Experiment 2b the same preexposure treatments had no effect on the acquisition of a discrimination between B and D. In Experiments 3a and 3b, rats given preexposure to C learned a discrimination between A and E more readily than those not given preexposure. Experiment 4 demonstrated that preexposure to a texture (e.g., B) that was adjacent to the to-be-discriminated textures (e.g., C and E) facilitated a discrimination between them relative to preexposure to their midpoint (D). These novel perceptual learning effects are interpreted as reflecting a redistribution of processing between the notional elements of the texture dimension.